How to insert space or make a gab between many joined stripped pieces of Audio VSE?
There are at least two fast methods:

First method

Inside the VSE, deselect all strips then, press b and drag your mouse to box select the strips you want to move. When you have selected them, press g to grab all of them and move them by the desired amount with your mouse. Finish with LMB.

Second method

Inside the VSE, place your cursor inside the strip after which you want to insert the gap with LMB. Then select Strip -> Insert Gaps or press Shift+= and it will insert a gap after the current strip. This is actually the reverse of the method mentioned in the question you linked.

Hope that helps.